Solvent-dependent oxidative triflamidation of alkenes and N(O)-Heterocyclization of the products

Regioselective Oxidative Halotriflamidation of Dienes and Trienes as a Route to New Amidines and Heterocycles

“…The non‐conjugated analogue of diene 7 , cyclohexa‐1,4‐diene 9 , in the presence of NBS reacts similarly, to give the corresponding bromoamidine by addition to one double bond [12] . With t ‐BuOCl/NaI as the oxidant in MeCN, diene 9 afforded N,N′‐(4‐chloro‐5‐iodocyclohexane‐1,2‐diyl)bis(triflamide) by addition to both double bonds but without solvent interception [29] .…”

“…Thus, bromoamination of styrene with tosylamide in the presence of NBS proceeds in a low yield and affords a mixture of the regioisomers in the ratio of 3 : 2, whereas with different metal‐based catalysts the yield may reach 97 % with excellent regio‐ and diastereoselectivity [14] . As we have shown recently, the NBS‐induced sulfamidation of alkenes in acetonitrile occurs with solvent interception to give the Ritter‐type products, amidines [16] . Without external source of halogen, amidines can be formed using N,N‐dichlorosulfonamides as pre‐activated electrophilic reagents in acetonitrile also proceeding with solvent interception [17] …”

“…To study the synthetic potential of the synthesized bromoamidines, we investigated the possibility of formation of imidazolines via elimination of HBr from amidines 15, 17, 18 by the action of K 2 CO 3 , as in our previous works. [12,34] Indeed, the corresponding imidazolines 26-28 were obtained in close to quantitative yield (Scheme 14).…”

“…[30] The non-conjugated analogue of diene 7, cyclohexa-1,4diene 9, in the presence of NBS reacts similarly, to give the corresponding bromoamidine by addition to one double bond. [12] With t-BuOCl/NaI as the oxidant in MeCN, diene 9 afforded N,N'-(4-chloro-5-iodocyclohexane-1,2diyl)bis(triflamide) by addition to both double bonds but without solvent interception. [29] In order to investigated the effect of the oxidant, we performed the reaction of diene 9 in the presence of PhI(OAc) 2 /I 2 (for pioneering studies see, e. g. [31] ) and obtained amidine 21 as the product of iodotriflamidation at one double bond with solvent interception (Scheme 8).…”

“…[14] As we have shown recently, the NBS-induced sulfamidation of alkenes in acetonitrile occurs with solvent interception to give the Ritter-type products, amidines. [16] Without external source of halogen, amidines can be formed using N,N-dichlorosulfonamides as pre-activated electrophilic reagents in acetonitrile also proceeding with solvent interception. [17] Cyclic ethers, such as tetrahydrofuran and ethylene oxide, can also be incorporated in the products of bromoamination after the ring opening.…”